Rock-drilling engine.



PATBNTED MAY 31, 1904.

L. DURKBB. ROCK DRILLING ENGINE.

' APPLICATION rmm APR. 27. 1903.

6 SHEETS-SHEET 1.

10 MODEL.

PATENTED MAY 31, 1904. L. DURKBE. ROCK DRILLING ENGINE.

APPLIOATION nun APR. 21. 1963.

B SHEETS-SHEET 3.

N0 IODEL.

PATBNTED MAY 31, 1904.

L. DURKEE. ROCK DRILLING ENGINE.

APPLICATION FILED APR. 27. 1903.

6 SHEETS-SHEET 4.

K0 MODEL.

PATENTED MAY 31, 1904.

L. DURKEE. ROCK DRILLING ENGINE.

APPLICATION TILED APR. 27. 1903.

6 SHEETS-SHEET 5.

N0 MODEL.

No. 761,153. PATBNTED MAY 31, 1904.

L. DURKEE. ROCK DRILLING ENGINE.

APPLICATION PILED APR. 27. 1903.

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76 wii 7/ v UNITED Y STATES Patented May 31, 1904.

PATENT OF ICE.-

LAFAYETTE DURKEE, or DENVER, COLORADO.

ROQK-DRILLING ENGINE.

' SPECIFICATION forming part of Letters Patent No. 761,153, dated. May 31, 1904.

Application filed April 27, 1903.

To all whom it mag concern: I

Be itknown that I, LAFAYETTE DURKEE, a citizen of the United States of America, residing in the city and county of Denver and State of Colorado, have invented certain new and useful Improvements in Rock-Drilling 'Engines; and I do declare the following to be a full, clear, and exact description of the inven: tion, such as will enable others skilled in the art to which it appertains; to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specification.

My invention relates to improvementsin rock-drilling engines; and the objects of my invention are, first, to provide a motor-operating rock-drilling engine of the hammer-piston type; second, to provide a motor-operated rock-drilling engine of the hammer-piston type in which the piston is actuated by coiled springs which are reciprocated byan oscillating crank-arm and a cross-head; third, to provide a spring-actuated piston-hammer drill in which the drill-bit is turned step by step directly by the piston and 'in which the rifle bar and pawl and ratchet mechanism commonly used for turning the rock-cutting drill-bit is dispensed with; fourth, to provide means for instantaneously relieving the strain on the piston and of the step-by-step rotating mechanism of the rock-cutting drill-bit when said drill-bit strikes into a seam in the rock and is thereby held from being turned by the piston, thus preventing breakage of the parts comprising the drillturning-mech anisrn; fifth, to provide means for adjustably cushioning the backward or recoil stroke of the hammer; sixth, to provide means by which a rock-cut} ting drill-bit can be manually locked to or unlocked and removed from the drilling-engine almost instantly; seventh, to provide a piston hammer rock-drilling engine through which a supply of water is conveyed from the drillingengine through the rock-cutting drill-bit to its cutting-point and to the bottom of holes in rock while drilling them; I attain these objects by the mechanism illustrated in the accompanying drawings, in which Figure 1 is a side elevation of my improved Serial 1:... 154,487. (No model.)

rock-drilling engine supported in a tunnel on astoping-bar operatively connected bya flexibleshaft to an electric motor and to a watersupply tank which is provided with an airpump that is adapted to place the water therein under pressure. Fig. 2 is a plan view of my improved rock-drilling engine. Fig. 3 is a longitudinal sectional elevation of the same. Fig. 4 is a section of Figs. '1 and 2 on lines A and B. Fig. 5 is a section of Figs. 1 and 2 on lines C and D. Fig. 6 is a perspective view of the pistons rearward extension, showing a straight fluted portion at its end, a straight fluted nut in which the fluted end of the piston reciprocates, and the ratchet-wheel which prevents the piston-hammer from rotating in but one direction. Fig. 7 is a fragmentarysection of that portion of the casing of the drilling-engine that supports the ratchet and fluted nut and fluted end of the hammerpiston shown in Fig. 5. Fig. 8 is a perspective view of one of the ratchet-locking pawls. Fig. 9 is asectional view of the sliding socket in which the pawls of the pistons ratchet-wheel are slightlyincased. Fig. 10 is an end elevation of Fig. 8, showing the spring-holding recess in the end of the socket opposite the pawl-socket end. -.Fig. 11 is a plan view of the pawl-socket and of Figs. 9 and 10. Fig. 12 is a section of Figs. 1 and 2 on lines E and F.- Fig. 13 is a section of Figs. 1 and 2 on lines Grand-H. Fig. 14 is a fragmentary perspective sectional view of the casing, showing the rifled hammer-piston and the drilling turning sleeve in operative relation. Fig. 15 is a longitudinal sectional view through the front cylinder-head. Fig. 16 is a transverse sectional view through the front cylinder-head and parts contained therein on the-line 16' 16, Figs. 2 and 3. Fig. 17 is a sectional view through the drill-bitlocking portion of the sleeve, showing one of the drill-bit-locking blocks in an unlocked position in dotted lines. Fig. 18 is a sectional view through the drill-bit-supporting and water inlet connection of the front cylinderhead. Fig. 19 is a perspective view of the rock-cutting drill-bit. Fig. 20 is a perspective view of one of the drill-bit-locking blocks: Fig. 21 is a transverse sectional view, reduced, through the rock-drilling engine on the line tion 10, which rests against the side of the 21 21, Fig. 2. Fig. 22 is a view of the operating crank-shaft, and Fig. 23 is a sectional elevation of the mechanism I employ to couple the driving-gears of the driving-engine to the flexible driving-shaft.

Similar numerals of reference refer to similar parts throughout the several views.

Referring to the drawings, .the numeral 1 designates the casing of my drilling-engine. The bottom of the casing is provided with guideways 2 and 3, which fit reciprocatively in slideways 4 and 5, formed in a supportingshell 6. The bottom of this shell is provided with a diverging beveled hub 7, which is clamped to suitable tripods or stoping-bars, which I do not illustrate, but which support the shell and drilling-engine inoperative positions in shafts. stopes, and tunnels of mines. The bottom of the casing is provided with a depending lug 8, which is provided with an aperture 8 through which projects a Hut '9, that is provided at one end with a head porlug. The opposite end of the nut projects through the lug an is threaded, and a nut 11 fits the threaded e d and screws against the opposite adjacent e d of the lug. 1

The nut 9 is provided with a threaded hole,

which extendsthrough it in axial alinement with theguideways of the casing and shell.

A feed-screw 12 is threaded'tothe nut and extends through it to the opposite end of the shell. The end of this screw adjacent to the nut 11 is provided with a collar 13 and square terminal end portion 14, on which fits loosely a crank 15, which is provided with a split hub 15, that is secured to the square end of the feed-screw by a clamp-bolt 15. The hub is also secured on the square end and against the collar by a nut 16, which is threaded to the end of the screw. The crank end of the screw is supported by rods 17 and 18, which are securcd'at one end to lugs 19, which project from opposite" sides of the collar, and at their opposite ends to projecting cars 20, formed on the adjacentend of the casing.

The casing 1 is a long substantially cylindrical-shaped casting, the opposite ends of which are provided with bolt-flanges 22 and 23. The front bolt-flange 22 issecured by bolts 24 to a front cylinder-head 25, and the rear bolt-flange 23 issecuredby bolts 26 to a rear cylinder-head 27. I

The central portion of the cylindrical casing projects upward and forms a hood portion, intowhich two openings 28 and 29 are preferably made, which are normally closed by covers 30 and 31; The covers 30 and 31 are secured-to the openings by screws 30'.-

and on one end a fly-wheel37is preferably hub I secure a bevel-gear 38.

mounted. Upon the opposite end close to the I A reduced portion 39 of the crank-shaft extends beyond the gear 38, and a casing 40 is secured pivotally to the end of the crank-shaft on a reduced shouldered terminal end portion 40*, which is threaded. The gear 38 is provided witha hub portion in which arecess is formed. The casing is divided into two sections, which overlap at one of their ends and are secured together by screws 40 and their free ends project loosely and pivotally into the hub of the gear 38. This casing is provided with a hub 42, through which projects a short shaft 43, upon the end of which, inside of the casing, I secure a bevel-gear 44, which means of a coupling which is made uppar-- tially of said shaft, which is formed into a The opposite half-shaft throughout the greater portion of its length. A socket 43 is also formed with ahalf-shaft portion 43? to overlap the flattened short shaft of said gear, so that both together form a round shaft. The socket 43* comprises thishalf-shaft portion 43 and a head portion 43 which forms an integral portion of said half-shaft, and a-threaded bore 43 is formedin'the center ofthis head portion.-

The hub portion 42 of the casing is provided with an axial bore '42, through which the combined half-shaft of the bevel-gear 44 and of the socket 43 extend and rotate. A sleeve 42 is loosely-mounted on the hub of said casing and is connected thereto by any suitable manually-operating lock-joint 43 such'as a bayonet-joint. Its opposite end is threaded to the covering 42 of the flexible shaft. The

flexiblesha'ft' 45'- consists of the covering 42 and is provided with a stem 42 which is threaded to the head of the socket and drives hood in the hubs 34 and 35, upon which is secured a crank-arm 48. The crank-arm is secured to the shaft. at the center of its bend portion intermediate-of its ends, and one arm 1 48 extends horizontally and contains a guideway-slot 49, in which is slidably mounted a box 50, which is made in two halves and contains an aperture, made partially in each half, which fits operatively on the crank-pin 51 of the crank shaft. The opposite end of the crank arm depends vertically from the bend of the crank-arm, and its end is bifurcated into two arms 48 and 48, each of which contains a vertical slot 52, in each of which is slidably mounted a box 53 and 54, containing an-aperture in which is operatively mounted the trunnions 53 of a cross-head 55. This cross-head surrounds loosely a piston-rod 56, which extends axially through the cylindrical casing. This cross-head has atendency to throw downwardly under its high reciprocal speed, and a slideway-gib 55 is provided for it to rest on and on which it is slidably supported. This gib or slideway supporting strip is secured by screws 55 to an upwardly-projecting portion 55 of the bottom of the casing. The gib is provided at its ends with projecting lips 55, which fit down over the ends of the upwardly-projecting portion of the casing. The gib is preferably made a trifle shorter than the reciprocal stroke of the cross-head in order that its surface may wear down evenly.

The piston-rod 56 I preferably make of tubing.. It is secured to a hammer 57, preferably by means of a threaded connection, the end of the piston-rod being threaded. A hole 58 is bored axially into the hammer of larger diameter than the piston, and a smaller hole 59 is drilled inthe bottom of .the hole 58. This bore 59 is threaded to receive the threaded end of the piston-rod. In the larger hole 58 I place an expansive spring 60, and against the end of this spring and the end of the hammer I place a buffer-washer 61, which is mounted loosely on the piston-rod. Between the buffer-washer 61 and the cross-head I mount a spring 62 loosely on the piston-rod, which is under expansive tension enough to hold the washer 61 against the hammer. The end of the hammer to which the piston is secured is slidably mounted loosely in a cylindrical bore 63 in the casing. The periphery of the hammer is provided with spiral flutes 64, which reciprocate freely in a fluted nut 65. This fluted nut is threaded to the adjacent end of a sleeve 66, whichIcall the drillbit-rotating sleeve. This sleeve is rotatably seated in a counterbore67, formed in the cylindrical casing and which extends from the front cylinder-head flange to the cylinder-bore 63, in which the rear end of the hamlneris loosely mounted. To the bolt-flange 22 of the front end of the casing I secure the front cylinder-head 25 by means of bolts 24, which pass through bolt-holes formed in a flange 70, which forms an integral part of the front cylinder-head. This front cylinder-head projects forward from its bolt-flange in the form of a sleeve and forms a supporting-casing for the front end of the sleeve 66. An enlarged portion 7 0 is formed at a short distance from the flange end of the cylinder-head, which is provided with a large opening in each side and leaves flat strips of metal 71 and 72 at the top and bottom of the cylinder-head, and from this enlarged portion the lower part of a box 74 extends axially forward and supports a rockcutting drill-bit 75. A cap 76 forms the other part of the box 74 and is secured thereto by bolts 77, which pass through laterally-projecting flanges formed on the sides of the two parts of the box. The sleeve 66 projects from the casing into the front cylinder-head to close to the farther end of the side openings from its casing-connecting end. A counterbore 78 is formed in the end of the front cylinder-head, that connects to the casing, and in the peripheral edges of this counterbore I form recesses 79, which also extend into the shell of the cylinder-head from the face of its bolt-flange. I preferably use two recesses, although three or more may be employed, if necessary, and place them diametrically opposite one another. In each of these recesses I placearatchet-tooth pawl 80, which I pivotally mount on pins 81, which extend beyond the pawls into holes 82, drilled into the side of the bolt-flange of the casing. (See Fig. 13, which is an end view of the boltflange of the casing.) Similar holes are drilled in the side walls of the recesses. A recess 82 extends from each of the pawl-holding recesses. These recesses extend from the inner periphery of the counterbore into the shell of the front head. In each of these recesses I secure a spring 83 and 84, preferably using a wire spring. in which I form a coil intermediate of its ends. I place the coil around a pin 84, which projects across the recess into its side walls. One end of the spring hooks over a pin 85, and the opposite end bears with resilient pressure against the top of the adjacent pawl.

In the counterbore 78 I place a ratchet-ring 87, which fits revolubly therein and is provided with an axial bore that is interiorly threaded. The drill-bit-rotating sleeve 66 is also slightly enlarged at this point for a distance equal to about the length of the counterbore, and the enlarged portion is threaded and terminates in a collar 87", which fits revolubly in a counterbore formed to receive it at the end of the counterbore 78. The ratchetring 87 screws on the threaded portion of the sleeve against the collar.

The peripheral surface of theratchet-ring 87 is provided with ratchet-teeth 88, which the spring-controlled pawls 8O operatively engage. V The shell of the drill-bit-rotating sleeve is much thicker at and adjacent to its free terminal end portion and contains a rockcutting-drill-bit-receiving aperture 90, which extends into the piston-chamber 91 of the sleeve, and at the junction of the piston-chamber with the bottom of its bore, which forms a shoulder at the end through which the drillbit aperture extends, I form a small circumferential groove, in which I place a suitable buffer-ring 92, adapted to receive and cushion the blows of the hammer when the cutting-point of the drill-bit is not against rock. This buffer-ring is fitted tight in the chamber of the sleeve and is driven into its counterbore, where a few blows of the hammer will expand it into the counterbore sufficient to confine it there.

The shank 93 of the rock-cutting drill-bit fits loosely into the aperture of the sleeve, and the end extends through it into the hammer-chamber a short distance into the striking path of the hammer. from the end of the shank I form two fiatbottomed recesses 94 and 95, placing them on opposite sides of the shank and opposite one another. the aperture in the free end of the sleeve, and transversely through the shell of the sleeve adjacent to its end I form two slots 96 and 97 (see Figs. 8, 14,) one at the top of the sleeve over the drill-bit and the other in the bottom of the sleeve under the drill-bit. These slots register with the fiat-bottomed recesses in the shank of the drill-bit adjacent to their shouldered ends 94 and These slots in the sleeve are formed to leave two flat parallel bars of metal 98 and 99, (see Figs. 16, 17,) one on each side of the drill-bit aperture. In each of the slots 96 and 97 I fit loosely segmentalshaped blocks 100 and 101, (see Fig. 16,) which are fitted to fill the slots and round out the peripheral surface of the sleeve. These blocks is shown in dotted lines held above the bars and drill-bit aperture by its springs) to allow the shoulders 94 and 95 of the terminal ends of the flattened portions 94 and 95 and the end of the drill-bit to pass freely in and out.

of its receiving-aperture in the sleeve. These blocks are adapted to lock the drill-bit in the sleeve, and they accomplish this by being pressed on their springs against the surface of the integral bars of metal, which brings their flat side between the shoulders of and close to the surface of the flattened places on the shank of the drill-bit. The moving or pressing of the blocksagainst their springs is accomplished simultaneously by means of a slidingcollar 110, which is mounted loosely on the sleeve and which slides over the blocks, the end of the aperture that passes over the blocks being flared or tapered outward to permit it to be readily pushed over them. The dowels b will prevent any lateral displacement of the blocks as they are raised by the springs 106 107 108 109.

An expansive spring 111 is mounted on the sleeve and bears resiliently between the rear side of the collar and the adjacent shoulder of At a short distance These recesses normally lie within the opening in the sides of the sleeve and holds the collar on the blocks. A collar 112 is secured, preferably by screws 112, on the end of the sleeve and acts as an abutment or stop for the block-holding collar, which is held against it by the spring. This block-holding collar is adapted to be moved by the hand of i an attending operator inserted through the open space in the sides of the casing to lock or to release the drill-bit from the sleeve. The drill bit is thus locked by the blocks formed on the opposite sides of the drill-bit between the shoulders 94, 95 and 94 and 95 and the drill-bit is prevented from turning in the sleeve by the flat bottom of the blocks resting close to the flattened places which form the bottomsof the recesses 94 and 95. These recesses are made enough larger than the thicknesses of the blocks to allow the drillbit a longitudinal movement independent of the sleeve and the drilling-machine suflicient to allow the drill-bit to be driven by the hammer ahead through the sleeve and cylinderhcad against the rock. The drill-bits entrance 113 into the end of the cylinder-head is larger in diameter than the bore of the box in which the drill-bit rests, and just inside of the entrance a counterbore 114 of larger diameter than the entrance-bore is formed. In the rear end of the counterbore a coiled spring 115 is placed. A washer 116 is also placed in the counterbore at the outer or front end of the spring. Upon the drill-bit I form, preferably integrally with the shank, an annulus or collar 117, which is positioned to stand against or close up to the washer and wholly inside of the counterbore when the striking end of the drill-bit is in operative striking relation to the hammer.

The collar is made enough smaller in diameter than the entrance-aperture into the box to permit it to move freely in and out of it.

They washer and spring form a resilient buffer for the collar to strike against and receives the recoil movement of the drill-bit after it has been driven against rock by the hammerand prevents the shoulders 94 and 95 from striking against the adjacent sides and edges of the blocks 100 and 101. The drill-bit projects loosely through the box of the front cylinder-head, so that it can be I. preffrom its cutting-point to within a short distance of its opposite end, which is intersected by a hole 119, that extends into its side.

The bore of the box 74 in the end of the cylinder-head is provided with two circumferential grooved portions, 120 and 121, one being placed'on each side of the entrance to the water-passage. These grooves are filled with a suitable packing 122 and 123, which is arranged to pack the'shank of the drill-bit by screwing down the cap of the box. In the partition 124, of metal, left between these packing-receiving recesses I form a circumferential recess 125,which I make long enough to allow the entrance of the water-passage to connect with it during the drill-bits independent operative movement when being struck by the hammer. Through the cap portion of the box I form a threaded hole 126, which extends into the circumferential recess 125. To this threaded hole I thread a short piece of pipe 125*, fitting it so that it will fit snugly, but at the same time so that it will turn or swivel easily. To the end of the pipe 125 I thread an elbow 125 and to the elbow a nipple 125 and to the nipple a valve, and to the valve one end of a hose 127 by means of a threaded connecting-nipple 128, which is secured to the-hose and to the valve. This valved angle connection permits the supply of water to be regulated and the flowing to the cutting-point of the drill-bit to be regulated, and the swiveling-nipple permits the position of the hose and the angled-pipe connection to be shifted to either side of the drilling-engine as desired. The hose'leads to a suitable supply of water or other suitable rock-cuttings-removing fluid, which is arranged to flow through the hose under suflicient head-on pressure to wash the rock-cuttings from the holes in rock while drilling them. This feature of my invention I preferably carry out in the following manner: I place a small portable tank 127 A adjacent to the drilling-engine. I provide this tank with a hand-operating air-pump 127 which is connected 'to the top of the tank by a tube 127 A pressure-gage127 is preferably placed in the hose between the tank and the pump, and the hose 127 is connected to the bottom of the tank. The tank is adapted to hold enough water to last some time and is filled nearly full of water or any other suitable watery fluid, which is placed under sulficient pressure to force the rock-cuttings from downwardlyextending vertical holes by an attcndants pumping air into it frequently enough to maintain a pressure sulficient to give the water the desired pressure.

A rear cylinder-head 27 is bolted by bolts 26 to the bolt-flange of the rear end of the casings, which pass through projecting lugs 27, which form a part of a flange formed on the end of the cylinder-head. This rear cylinder-head extends rearward of the casing in the form of a cylindrical hood. A counterbore 132 extends into it from its flanged end, in which a ratchet-ring 133 is loosely seated. The periphery of the ratchet-ring is provided with ratchet-teeth 134, while its interior periphery is threaded and screws onto a threaded step portion formed of the periphery of a nut 135, which is revolubly seated partially in the counterbore 132 and partially in a counterresilient bufl er-pawlcarrier 143. This bufferpawl carrier comprises a block 144, which fits slidably in the chamber.

one end of a coiled expansive spring 145 fits loosely, the opposite end of which bears against :the bottom of the chamber. of the block a circular aperture 146 is formed,

In the front end which extends through the block, preferably in parallel 'alinement with the length ofthe ratchet-teeth of the ratchet-ring 133. The

peripheral edge of this aperture cuts through the end of the block, leaving substantially two-thirds of the aperture within the block. In the aperture I place the head 146 of the pawl 142. The head of the pawl is round and fits pivot-1y in the circular aperture, while the body' of the pawl projects through the open end to its tooth which rests on and engages the teeth of the ratchet-ring. The pawl is held in engagement with the ratchetwheel by a spring 149, one end of which is coiled round a pin 150, that extends across a recess 151, which is formed in the top of the block to receive the spring, While the opposite end extends through a slot 151, formed in a depending lug 152, formed on the adjacent .wall of the chamber, and bears resiliently on .the top of the tooth end of the pawl.

The pawl-carrying buffer-blocks are inserted sidewise into the chambers which open out at the flange end of the rear cylinder-head, and the expansive spring normally holds them for- In the rear end of, the block a chamber 145 is formed, in which ward against the depending lug 152, which projects into the chamber at the front end of the block, and are positioned to normally hold the pawls in operative relation to the ratchetteeth of the ratchet-ring and also to allow a rearward bulfer or yielding cushioning movement of the'pawls and blocks away from the ratchet-ring and against the coiled expansive springs in the bottoms of the chambers, the object of which is to provide an automatically-yielding drill-bit rotating and holding mechanism that Will give back when the drillbit strikes into and sticks and runs into a seam or crevice in the rock and prevent breakage of the various parts of the drill-rotating mechanism, as will be explained more fully hereinafter. To the rear end of the piston-rod I secure a cylindrical piston-head 154, which preferably I secure to the pistonrod by a threaded connection 155, which I a form by providing the end of the piston-rod cross-head. The rear piston-head fits slidgearing to the crank-shaft;

ably in the nut 135 and extends through it into the hood portion of the rear cylinder head, and its periphery is provided with straight flutes 157, that fit slidahly in the straight flutes of the nut. An axial bore 158 is formed in the rear end of the rear pistonhead, in which is slidably mounted a buffer device which is adapted to cushion the backward or return strokeof the hammer-piston. This buffer device comprises a piston-head 159, a piston-rod 160, which is adjustably secured to the end of, the rear cylinder-head, and a spring 163.

The piston-rod extends slidably through the end of the-rear cylinder-head. Its free endis threaded and is provided with nuts 161, which screw-against the end of the rear cylinder-head. Upon the piston-rod and against the inner end of the rear cylinder-head I place a-washer 162, and between this washer and the piston-head -I place around the piston-rod a coiled spring 163, which is under an adjustable expansive tension that may be regulated by the nuts by screwing up or unscrewing the nuts 161 at the end of the piston-rod. The operation of my improved piston-hammer rock-drilling engine is as follows: 1 The drilling-engine is operatively supported in tunnels by a stoping-bar 162 which is braced between the roof and floor, as shown in Fig. 1, or between the side walls of tunnels or shafts of mines. Any suitablemotor maybe employed to operate my drilling-engine, and the motor may be connected to it by any suitable means of transmitting power, or, if' desired, the motor may be mounted directly on the engine and be connected directly or through the medium of I preferably employ, however, an electric motor-foroperat ing my-drillingengine, as shown in Fig. 1, which I set adjacent to it and connect the motor to the flexible shaft by any suitable connection and then connect the flexible shaft 45- to the bevel-gear 44, as shown in Fig. 23. The motor is connected to anysu'i-ta-ble electric current and-rotates the flexible shaft 45 and the bevel-gears 44 and 38, through which power is transmitted to the crank-shaft 36, which should be rotated in the direction of the arrow 164. The crank-pin 51 thenreciprocates the box in the slideway of the horizontal arm of the crank-arm 48, causing it to oscillate rapidly in its axial bearings at right angles to the longitudinal axis of the piston-hammer, by which I mean the combined hammer 57, piston-rod 56, and. rear piston-head 154, which causes the depending arm to reciprocate in a.

direction substantially parallel with the longitudinal axis of the hammer-piston, which reciprocates the cross-head on the piston-rod 56 of the piston-hammer.

On the forward stroke of the depending arm of the crank-arm the cross-head which is loose on the piston-rod is forced forward with a short quick jerk, which forces the spring 62 to drive the hammer with great force against the end of the drill-bit. The quick forward jerk or' movement of the crosshead spring and hammer is caused by the crank-pin as it passes its horizontal center on its downward movement, as it moves much closer to the pivotal axis of the crank-arm on its down movement than it does on its upstroke, which forces the depending arm and the cross-head spring and the piston-hammer to-move one-third quicker on their forward stroke than on the backward stroke. As soon as the crank-pin passes its lower center the direction of movement of the depending arm and cross-head is reversed and the cross-head moves the spring 156 against the rear pistonhead and forces the piston-hammer backward on its return stroke.

When the crank-sh aft is running from about eight hundred to twelve hundred revolutions per minute, the'piston-hammer reciprocates just as fast and strikes blows forcibly enough to drill rock fast with piston-hammers weighing from one-half to one-third less than the weight of plunger drill-bars used in drilling engines and machines of the plunger type. I

am able to accomplish this becausemy lightweight piston-hammers enable me tostrike a great many more blows per minute and by striking directly on the end of the drill-bit to strike more effective rock-cutting blows with less power. and less wear of the parts of the machinery. Iam alsoable to make thedrilling-machines smaller and lighter in weight than is possible with the plunger type of rockdrilling machines.

' As the cross-head reciprocates very rapidly, the springs throw the hammer forward with great force and often will drive the'drill-bit ahead of the piston-hammers normal striking stroke, which is always the case when the machine is not fed forward by the feed-screw 12 as fast as the drill-bit'cuts into the rock. The cross-head will then reverse its movement before the piston-hamm'erreaches the end of its forward stroke and will compress the rear spring 156 and cushion the forward stroke of the piston-hammer. On the backof the nut 135.

ward stroke of the piston-hammer the rear piston-head strikes the adjustable springbuffer device that is positioned between it and the rear cylinder-head and resiliently cushions the backward stroke of the pistonhammer and starts it forward again and relieves the forward hammer-actuating spring 62 of severe cushioning strain when the hammer starts it forward and in a large measure relieves the forward hammer-actuating spring of the severe cushioning strain when the cross-head reverses it from its backward to its forward stroke.

The spring 60 exerts an expansive pressure on the washer 61 and serves to hold it against the end of the spring 62 and also holds the opposite end of the spring 62 against the cross-head. Consequently when the pistonhammer does throw forward after the crosshead has started back the spring 60 will expand and fill the increased distance between the hammer and the cross-head and prevent any looseness and rattle of the piston-hammers actuating-spring. Should the actuating-spring be loose between the hammer and cross-head, they strike it before they compress it when they reverse their direction of movement, and this hammering action is apt in time to crystallize and break it.

The piston-hammer springs 62 and 156 form a resilient flexible actuating device and a yielding connection between the cross-head and the hammer and rear piston-head that in a measure permits the piston-hammer a variable reciprocal stroke independent of the fixed reciprocal movement of the cross-head. As the pistonhammer operatively reciprocates against the drill-bit the spiral flutes of the hammer reciprocate in the spiral flutes of the nut 65. At the same time the straight flutes of the rear piston-head reciprocate in the straight flutes The flutes in the rear nut and on the piston-head operate to hold and support the piston-hammer in alinement with its longitudinal reciprocating movement, and the pawls 142 prevent the ratchet-ring 133 from rotative movement except in the direction of thearrow 165, and the rear ratchet is turned by the reciprocal movement of the hammer in the spirally-fluted nut 65, as this nut is also looked against rotative movement except in the direction of the arrow 165 by the ratchet-ring 87 and the pawls 80. )onsoquently the front and rear ratchet-wheels are arranged to rotate in the direction of the arrow 165, but are locked by their pawls against rotative movement in the opposite direction, and as thepiston-hammer moves forward to strike the drill-bit the front nut and ratchet remain stationary, as the front nut and its ratchet-ring move back against their pawls 80, and the spirally-fluted nut is prevented from turning. Consequently as the piston-hammer moves forward to strike the drill-bit the spirally-fluted nut forces it to turn a rotative distance in the direction of the arrow 165 equal to the pitch of the spiral flutes, and this rotative motion rotates the straight fluted nut and its ratchet-ring away from its bufler-pawls.

On the backward stroke of the piston-hammer the tendency of the spiral flutes of the hammer is to turn the hammer in the opposite direction from the arrow 165. The hammer is, however, prevented from turning in that direction by the buffer-pawls. Consequently the piston-hammer is forced to move straight back in the straight flutes of the nut 156, and the spiral nut, the drill-bit-rotating sleeve, and the drill-bit are forced by the spiral flutes on the hammer to rotate in the direction of the arrow a distance equal to the pitch of the spiral flutes of the hammer. Consequently the drill-bit is rotated at each backward stroke of the hammer and always strikes in a new place in the bottom of holes being drilled in successive rotative step-by-step order as the piston hammer reciprocates. When, however, the drill bit strikes and sticks and keeps striking and sticking in a seam, it is necessary to feed the drill-bit back and then feed it forward slowly and carefully. Consequently when the drill-bit first enters a seam and sticks or enters a crevice in which it has longitudinal movement, but cannot be turned by the spiral-fluted nut and i1l18 drill-bit-rotating sleeve, the piston-hammer on its back stroke must turn backward-in the spiral flutes of the spiral-fluted nut, as it is impossible when the drill-bit is thus confined for it or them to turn in either direction, or some of the parts must break or the drillingmachine must stop short on the instant or the motor burn out, and it is consequently necessary in drilling-engines of this character to provide a backwardlyyielding pawl andratchet device that will resiliently yield backward a distance equal to the rotary-feed step of the drill-bit rotary-feed mechanism.

1 have found byextensive practical use of electric-motor-operated drilling-engines that when the drill-bit gets caught in a seam or stuck the motor will not stop. Instead it gathers strength by the resistance of the machine to normal operative movement when the engine slows down, and if the engine stops part break. These bulfer-pawls operate to accomplish this in the following manner when the drill-bit is prevented from rotating at any one or at any number of the backward strokes of the hammer in the spirally-fluted nut from any cause at its rock-cutting point, or if from any cause the fluted nut and the sleeve will not turn on the backward stroke of the hammer of the piston the hammer-piston itself must turn backward, and in turning backward it turns the straight-fluted nut on the rear pistonhead backward andalso its ratchet-ring, the teeth of which push directly against the pawls and move them and their carrying-blocks back against their resilient springs without disturbing the operative relation of the pawls and the ratchet-teeth and without subjecting any of the parts to any straip whatever,

and thepiston can continue reciprocating without its speed being slackened and with the spiral nut and sleeve held against'turning in either direction or feeding regularly,

in which case the hammer-piston would turn in the direction of the arrow or turn forward on its forward strokes in the spiral nut and in doing so would turn its straight-fluted nut 135 and the ratchet-ring 133, so that the ratchet-ring 133 would turn or run from the buffenpawls, and the piston-hammer would turn backward on its backward strokes and would turn its straight-fluted nut 135 and its ratchet-ring 133 backward against the bufferpawls and push them back into their supporting-chambers until the drill-bit has cut its way through the scam or crevice. The drillbits can be inserted in and removed from the drilling-engine in a very few seconds and practically instantly by an operator sliding the collar 110 back against the spring 111 from over the blocks with one hand, which will permit them to bemovcd by their springs from the drill-bit-holding aperture and by then either inserting a drill-bit in the front cylinder-head and the drill-bit-holding sleeve or withdrawing a drill-bit from them with the other hand.

While operatively drilling holes a supply of water or a suitable fluid under a suitable head or pressure is fed from the tank 127 through the hose to the circumferential recess 125 in the box 7 1 at the front end of the front cylinder-head, and the water which is confined by the packings 122 and 123 to the recess flows into the aperture 119 in the side of the drill-bit as it rotates and flows through the aperture 118 in the drill-bit to its cuttingpoint, and consequently washes the rock-cuttings from the hole in the rock as it is being drilled.

The water washes the rock-cuttings away from the cutting-point of the drill-bit and from the hole being drilled as fast as the drillbit makes them and keeps the drill-bit cool and enables holes to be drilled much faster than is possible in the commonly-used method r of frequently removing the drill-bit from the hole and removing the rock-cuttings by hand with a spooning-tool.

While I have illustrated the preferred method of conducting a supply of water to the cutting-point of the drill-bit and also of the preferred construction of my drilling-engine, I do not wish to be limited to the details of construction as illustrated, as my invention contemplates, broadly, a piston hammerdrilling enginearranged and adapted to be reciprocally actuated by yielding flexible resilient members operated by a suitably-connected motor and arranged and adapted to strike upon the end of a rock-cutting drillbit operatively positioned within the reciprocal path of the piston-hammer and arranged to be substantially instantaneously inserted in or withdrawn from the drilling-engine and which is arranged and adapted to receive a supply of water under suitable pressure from any source at or adjacent to the drill-bit end of the drill- I ing-engine and convey it to the drill-bits cutting-point and to the bottom of holes in rock while drilling them and in which the rotary feed of the drill-bit is provided with a compensating device that will permit the motor and drilling-engine to run normally when the drill-bit-rotating mechanism becomes from any cause temporarily stuck, locked, and inoperative.

Having described my invention, I what I claim as new, and desire to secure by Letters Patent, is

1. In a rock-drilling engine, the combination with the casing and its screw-feed-sliding supporting-base, of a piston-hammer reciprocally mounted in said casing, a hammer having a spirally-grooved peripheral surface at one end, a spirally-fluted nut rotatably mounted on said hammer, a sleeve secured to said nut, a rock-cu tting drill-bit operatively and removably secured to said sleeve in relatively fixed position to said piston-hammer, means including coiled springs operatively mounted on said piston-hammer for reciprocating said pistonhammer against said d rill-bit, a straigh t-fiuted portion on the rear end of said piston, a straight-fluted nut rotatably mounted in said casing having its fluted portion in operative mesh with the straight flutes on said pistonhammer, a ratchet-toothed ring on said nut, and spring-controlled pawls arranged in operative relation to said ratchet-teeth and provided with a resilient buffer-support, substantially as described.

2. In a rock-drilling engine, the combination with the casing, of a piston-hammer reciprocally mounted in said casing, spiral flutes on the hammer end of said piston-hammer, a spirally-fluted nut rotatively mounted on the spirally-fluted end of said hammer, a rotatable sleeve secured to said fluted nut, a ratchet-ring mounted on said sleeve, spring-controlled pawls arranged in said casing in operative relation to said ratchet-ring, a drill-bit projecting into said casing and through the adjacent end of said sleeve into the reciprocal path of said piston-hammer, means for removably securing said drill-bit in said sleeve, means including buffer-pawls and a straight-fluted extension on said piston-hammer adapted to permit the piston to move rotatably backward when said'drill-bit sticks in seams in the rock, and means includingamotor for reciprocating said piston-hammer against said drill-bit, substantially as described.

3'. In a rock-drilling engine, the combination' with the casing, the front cylinder-head and the piston-hammer reciprocally mounted therein, a revoluble sleeve mounted in said casing, a drill-bit-receiving aperture in the end of said sleeve, a drill-bit extending loosely into saidcasing and through the aperture in said sleeve into the reciprocal path of said piston-hammer, flattened portions on opposite sides of that portion of said drill-bit that lies within the drill-bit-receiving aperture of said sleeve, slots in said sleeve adjacent to the fiattened portions of said drill-bit, suitable blocks arranged loosely in said slots adapted to be moved against the flattened portions of said drill-bit, a collar provided with a flaring aperture adapted to be moved over said blocks and force them into the recesses of said drill-bit,

resilient means for automatically raising said blocks out of engagement with the flattened portions of said drill-bit when said collar is removed, means for preventing lateral move-' ment of said blocks when raised, means for confining said collar on said blocks against accidental displacement, substantially as de scribed. r

4. In a rock-drilling engine, the combination with the casing, the front cylinder-head and the piston-hammer reciprocally mounted therein, having spiral flutes formed on the periphery of its hammer end, a rotatable drillholding sleeve mounted in said casing, a drillbit extending into said casing into the reciprocal path of the hammer of said piston, oppositely-arranged recesses in said drill-bit, blocks arranged in said sleeve to extend into said recesses, means including buffer-pawls and a suitable ratchet, operatively connected to said piston for preventing the drill-bit-rotating mechanism from breaking when said drill-bit is prevented from operatively rotat-' ing when drilling rock, and means for lock-i ing and releasing said drill-bit to said sleeve,"

substantially as described.

5. In a rock-drilling engine, the combination with the casing," the frontcylinder-head ment of said piston-hammer, means including a ratchet-and-pawl step-by-step rotating device operatively connected to said pistonhammer for rotating said drill-bit, means .in-

cluding opening and closing blocks or jaws for instantaneously inserting and removing the drill-bit in operative rock-drilling strikdngdistanc'e of said piston-hammer, substan' tially as described.

6. In a rock-drilling engine the combina tionwith the casing and the front cylinderhead, of a box comprising a body portion formed on the free end of said cylinder-head and a cap detachably secured to. said box, a Y

'drill-bit-holding aperture in said box having an entrance-aperture of larger diameter, than the drill-bit-holding aperture; a recess of larger diameter than the entrance of said box, extending into the box from the entrance, a

spring in said recess, a buffer-washer in said recess positioned to bear against said spring, a drill-bit adapted to fit loosely in said box and having a projecting collar or abutment positioned to stand normally within said recess and to recoil against said buffer-washer and spring at each recoil from a blow against rock, substantially as described.

7 In a rock-drilling engine, the combination of the casing and the front cylinder-head the divided box, and the drill-bit having a projecting abutment, witha buffer device operatively arranged in said front cylinder-head M in operative engagement with'said projecting abutment of said drill-bit, substantially as described.

8. In a rock-drilling engine, the combination with the casing, of a piston-hammer reciprocally mounted therein, provided with spiral flutes, a drill-bit operatively mounted in said casing and positioned to be struck by said hammer, means including a pawl-andratchet device connected with the spiral flutes of said hammer and with said drill-bit for ro tating said drill-bit step by step, a straightfluted portion on the rear end of said pistonhammer; a straight-fluted nut mounted loosely on said straightflutes; a ratchet-wheel mounted on said nut, spring-controlled pawls mounted in operative engagement with said ratchetv wheel and a resilient buffer-support for said pawls arranged and adapted to permit said pawls to reboundingly retreat, whenever the 'rotat ive feed movement of saiddri-ll-bit fails to operate,- substantially as described.

9. In a rock-drilling engine, the combination with the casing, the pistonhammer reciprocally mounted in said casing, the drillbit and the drill-bits rotary feed mechanism, of a straight axially-fluted nut rotatably mounted in said casing provided with a ratchet-toothed ring; spring-controlled pawls arranged in operative engagement with the if teeth of said ratchet-wheel; blocks in said pawls are pivotally secured; recesses said casing in which said blocks are slidably seated, stops to define the operative position of said blocks and pawls and expansive springs arranged to hold said blocks normally against said stops whereby said pawls are arranged to reboundingly yield and retreat in unison with a backward rotative movement of their ratchet-ring and said nut and a straight-fluted portion on said piston-hammer arranged and. adapted to fit reciprocally in said straightfluted nut, substantially as described.

10. In a rock-drilling engine, the combination of the casing, the spirally-fluted nut and sleeve rotatably mounted in said casing, the ratchet-ring secured to said sleeve, the springcontrolled pawls arranged in mesh with the teeth of said ratchet-ring and adapted to prevent said ratchet-ring and sleeve and nut from rotating in but one direction; a rockcutting drill-bit operatively secured in said sleeve and casing; a piston-hammer having a hammer-head extending through said nut and provided with spiral flutes fittingslidably the spiral flutes of said nut, a straight-fluted portion on said pistonhammer, a fluted nut mounted rotatively on said straight-fluted portion of said piston-hammer; a ratchetring secured to said nut; recesses in said casing adjacent to said ratchet-ring; blocks slidingly mounted in said recesses; expanding buffer-springs between the bottom of said recesses and said blocks; stops arranged in said recesses against which said blocks are held by said springs; pawls pivotally secured to said blocks and arranged in mesh with the teeth of said ratchet-toothed ring; and springs secured at one end to said blocks and arranged to hold said pawls in resilient engagement with said ratchet-teeth, substantially as described.

11. In a rock-drilling engine, the combination with the casing and the piston-hammer having a straight-fluted portion, a nut rotatively mounted in said casing in which said fluted piston-hammer is slidably mounted, a ratchet-toothed ring on said nut, and springcontrolled pawls arranged in operative relation to said ratchet-teeth and provided with a resilient buffer-support, means for reciprocating said piston-hammer in said nut and means for rotating said piston-hammer step by step, substantially as described.

12. In a rock-drilling engine, the combination of the casing, the piston-hammer, the straight-fluted nut and the ratchet-ring, with the tangentially-arranged recesses in the easing, the sliding blocks in said recesses, the buffer-springs and the pawls operatively supported in said blocks to engage said ratchetring, means for reciprocating said piston hammer insaid straight nut and means for rotating said piston-hammer in the direction said pawls will permit, said piston-hammer to normally rotate in, substantially as described.

13. In a rock-drilling engine, the combination with the casing of a rifled nut rotatably mounted in said casing, a rifled member mounted in said casing to reciprocate in said rifled nut, a ratchet-toothed wheel connected to said nut and spring-controlled pawls operatively positioned in resilient bufl'er-supports arranged to permit said pawls to be reboundingly moved tangentially backward by a backward rotative movement of said ratchet-wheel, means for reciprocating said rifled member and means for rotating said rifled member and said nut and ratchet-toothed ring step by step in the direction that will cause the ratchetteeth of said ratchet wheel to move away from said spring-controlled buffer-supported pawls, substantially as described.

14. In a rock-drilling engine, the combination of the casing, the reciprocating pistonhammer having a straight-rifled portion; the straight-rifled nut mounted loosely on said piston-hammer and rotatably mounted in said casing, and the ratchet-ring secured to. said nut, with spring-controlled backwardly-yielding rebounding pawls arranged in operative engagement with said ratchetring, a spirallyfluted portion on said piston-hammer, a sleeve provided with spiral flutes in its inner peripheral surface rotatably mounted in said casing and in the inner spiral flutes of which the fluted portion of said piston-hammer is reciprocally mounted and means for locking said sleeve against rotative step-by-step movement 9 5 tion with the casing and the piston-hammer,

of coiled springs arranged to reciprocate said piston-hammer, a hollow terminal end on said piston-hammer adjacent to the rear end of said casing, a piston-head slidably mounted in saidhollow terminal end; a rod extending from said piston-head through the end of. said casing; nuts threaded on the end of said rod and an expansion-spring on said rod between the bottom of said holloWterminal end and said casing, substantially as described.

16. In a rock-drilling engine, the combination with the casing, of a piston reciprocally mounted in said casing provided with a hammer at one end; a hollow head at its opposite end; a cross-head slidably mounted on said piston intermediate of said hammer and hollow head ends; a coiled spring on the end of said piston between said hammer end and said cross-head, a coiled spring on said piston between said hollow head and said cross-head, means including a motor for reciprocating said piston, a rock-cutting drill-bit operativel y arranged in said casing to be struck by the hammer of said piston, a spring-controlled buffer-piston and rod adjustably secured at one end to said casing and slidably mounted stroke of said piston, substantially as duescribed.

17 In a rock-drilling engine, the combination of the casing and the piston-hammer having a hollow rear end, a piston-rod adjustably secured to said casing at one end, a washer on said rod bearing against said casing, a head on the opposite end of said rod projecting into the hollow end of said piston, and upon which the hollow end of said piston reciprocates, and an expansive spring on said rod between its head and said washer, substantially as described.

18. In a rock-drilling engine, the combination with the supporting-shell, of a casing mounted therein, a feed-screwadapted to feed said casing in said shell, a rear cylinder-head secured to said casing provided with a rearwardly-extendin g hood portion, a piston-hammer reciprocally mounted in said casing, an axial bore in the rear end of said piston-hammer, and an adjustable spring-buffer pistonhead arranged in said bore and adapted to be struck by the bottom of said bore on the rearward stroke of saidpiston-hammer, a rod extending from said piston-head through said hood, a thread and nut on the end of said rod arranged to adjust the position of said buffer piston-head in the bore of said piston-hammer from the outside of said hood and an expansive spring between the inside of said hood and said buffer piston-head, substantially as described. p

19. In a rock-drilling engine, the combination with the casing, of a rear cylinder-head secured to said casing; a counterbore in said cylinder-head, a ratchet-toothed ring revolubly mounted in said counterbore, a counterbore in said casing intersecting the counterbore in said cylinder-head, a rifled nut rotatably mounted in said counterbore and secured to said ratchet-toothed ring; recesses arranged in said cylinder -head tangentially to said toothed rings counterbore; sliding blocks in said recesses; expansive springs in the bottom of said recesses bearing resiliently against said blocks stops in said recesses to define the movement of said blocks, spring-controlled pawls pivotally mounted in said blocks arranged to engage said ratchet-ring, springs secured to said blocks and arranged to hold said pawls resiliently against said ratchetwheel a piston reciprocally mounted in said casing provided with a rifled portion arranged and adapted to reciprocate through said nut, and means for rotating said piston in predetermined step-by-step order in the direction to cause the teeth of said ratchet-ring to rotate away from said pawls, substantially as described.

20. In a rock-drilling engine, the combination with the casing of atubular-shaped front cylinder-head secured thereto, a counter-bore in said casing, a sleeve rotatably mounted in said casing and extending into said cylinderhead, a drill-bit extending through the cylinder-head end of said sleeve, means including a manually-operated slip-collar spring-controlled in one direction of its movement for removably securing said drill-bit in said sleeve and an open space formed in the sides of said cylinder-head for manually operating said collar to attach or detach a drill-bit to said sleeve, substantially as described.

21. In a rock-drilling engine, the combination with the casing and the piston-hammer; of a rock-cutting drill-bit comprising a drill-rod having a hammer-striking shank end and a suitable rock-cutting end and a collar adjacent to said shank end and having two flat-bottomed recesses placed diametrically opposite each other and positioned between said collar and its striking end, an aperture extending into said drill-bit from its side to its center and an axial aperture extending into saiddrill-bit from its rock-cutting end to intersect said sideentering aperture, substantially as described.

22. In a rock-drilling engine the combination with the casing, the crank-shaft and the fly-wheel and the bevel-gear secured to said crank-shaft with a casing pivotally secured to the adjacent end ofsaid crank-shaft, a hub portion on said casing, an aperture in said hub, a bevel-gear in said casing meshing with said bevel-gear of said crank-shaft, a shaft secured axially to said bevel-gear and rotatably mounted in the hub-aperture of said casing and having a portion of said shaft reduced to form a half-shaft, a socket comprising a head portion, a threaded hole in the said head portion, a half-shaft portion extending from said head portion and arranged to overlap the halfshaft portion of said gear in said casing and to extend into and rotate in the hub of said bevel-gear casing, a sleeve arranged to surround said socket and containing an axial bore in which said sockets head portion is rotatably mounted, a stem mounted in the axial bore of said sleeve and threaded at one end to said socket and provided with a hollow head portion, a suitable manually-operating lockjoint between said sleeve and said casing, a flexible shaft threaded at one end to said sleeve and having its core portion projecting into the hollow head of said stem anda suitable motor operatively connected to the opposite end of said flexible shaft, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

LAFAYETTE DURKEE.

Witnesses:

Gr. SARGENT ELLIOTT, BESSIE THOMPSON.

IIO 

